a) Field of the Invention
The invention is directed to an articulated fitting for seats with an adjustable backrest, in particular motor vehicle seats, in which a stationary articulated part associated with the seat part and a swivelable articulated part associated with the backrest are connected with one another via a swivel axle, with an adjusting and fixing device which determines the position of both articulated parts relative to one another and is constructed as a gear unit. The swivel axle of each articulated fitting has a central receptacle serving to connect with a transmission rod so as to be fixed with respect to rotation relative thereto, which transmission rod couples the two articulated fittings of a seat with one another.
b) Description of the Related Art
DE 30 13 304 C2 describes an articulated fitting of the type mentioned above in which the swivel axle has a cam portion or eccentric portion serving to support an articulated part. The eccentric portion is formed by two wedge segments which are inclined relative to one another and embrace regions of a driver of the swivel axle, as well as by a driver arm engaging between the narrow sides of the wedge segments, and by an energy accumulator which presses the wide sides of the wedge segments away from one another. The driver for the wedge segments is constructed as a disk or plate and is connected with the swivel axle portion so as to be fixed with respect to rotation relative thereto, e.g., by means of a press fit, shrink fit or the like. The disk-like driver can have integrally formed driver projections. In order to transmit torque from the articulated fitting arranged on one longitudinal side of the seat to the articulated fitting arranged on the opposite longitudinal side of the seat, a transmission rod is provided which engages in a non-circular recess of the swivel axle and accordingly couples the swivel axles of the two articulated fittings so as to transmit torque. In this prior solution, the recesses of each swivel axle are formed by a pocket hole with a hexagonal cross section into which the ends of a transmission rod can be inserted, these ends having an identical cross section.
When assembling the seat, i.e., when connecting the two articulated fittings on either longitudinal side of the seat by means of the transmission rod, the articulated part which is connectable with the backrest on one longitudinal side of the seat may be angularly offset relative to the articulated part which is connectable with the backrest and arranged on the opposite longitudinal side of the seat due to a nonuniform position of the swivel axles with respect to their angle of rotation. This angular offset is not noticed by the person assembling the seat because the angular discrepancy is too slight to be detected without auxiliary means. In this context, it is noted that in articulated fittings of the present type a 360-degree revolution of the swivel axle produces an angular displacement of roughly 10 to 12 degrees of the articulated part which is connectable with the backrest.